This invention relates to a display device, and more particularly to a display device adapted to permit a plurality of display units connected to carry out a series of displays.
A conventional display device is generally constructed in such a manner as shown in FIG. 3. The display device includes a plurality of display units 100. In FIG. 3, five such display devices 100 are arranged. The display units 100 are commonly connected to a host computer 101, so that the host computer 101 transmits display data to the display units 100 according to a predetermined communication format. Each of the display units 100 is provided with a dip switch, which functions to assign a number to the display unit corresponding thereto. When the display data are transmitted from the host computer 101 to the display units 100, each of the display units 100 determines whether or not the display data transmitted thereto are required by the display unit through the dip switch, resulting in taking necessary display data therein for displaying.
For example, when it is desired that the display device shown in FIG. 3 displays "A, I, U, E, O"; "A", "I", "U", "E" and "O" are transmitted to the first- to fifth stage display units for displaying, respectively.
As will be noted from the above, the conventional display device requires a dip switch to be provided for every display unit in order to determine the number of each of the display units, leading to an increase in manufacturing cost of the display device.
Also, the conventional display device is highly troublesome in operation because it is required to set a number for each of the display units through the dip switch. Further, in the conventional display device, erroneous setting of the number leads to a failure in correct displaying. In addition, when a variation in arrangement of the display units due to movement or shifting of the display units or the like is carried out, it is necessary to change over the set number of each of the display units.
Moreover, the conventional display device fails to permit the number of display units currently connected to the host computer to be known on the side of the host computer. In order to detect the number of display units, it is necessary to transmit the number assigned to the final-stage display unit by means of the dip switch to the host computer.